Eyebrow tattooing is a relatively minor cosmetic procedure widely practiced nowadays. Typically, eyebrow tattooing involves the use of a motorized machine which drives a single needle or a group of needles into vertical oscillation and thereby injects a liquid dye preparation into the skin in or around the eyebrow areas, so as to form continuous patches of permanent color markings intended to enhance the appearance of eyebrows.
Generally speaking, a conventional eyebrow tattoo machine consists of a transmission mechanism and a needle mounting mechanism, wherein the transmission mechanism is configured for driving the needle(s) in the needle mounting mechanism into reciprocal up-and-down motion along the central axis of the eyebrow tattoo machine. With such a machine, an eyebrow tattooist can use the pigment-dispensing needle tip(s) to tattoo the desired pattern, designed according to the customer's needs, on the customer's face. Once the eyebrow tattooing procedure is completed, the used needle(s) are removed and replaced by a new one or new ones for subsequent use. The replacement of used tattoo needles is to ensure the safety and sanitation of eyebrow tattooing and prevent the transmission of blood-borne diseases.
Please refer to FIG. 1 for an exploded perspective view of a conventional eyebrow tattoo machine 1. The eyebrow tattoo machine 1 is provided therein with a motor 10. The motor 10 has an eccentric shaft 100 extending outward from one end and is configured to drive the eccentric shaft 100 into eccentric rotation. Also provided in the eyebrow tattoo machine 1 is a transmission mechanism which essentially includes a cover 11, a swinging element 12, and a linking member 13. The cover 11 is penetrated by a receiving space 110 into which the eccentric shaft 100 of the motor 10 extends, and the bottom side of the cover 11 is concavely provided with two axial holes 111. The swinging element 12 is made of plastic and is bilaterally provided with a pair of pivots 120, each received in a corresponding one of the axial holes 111. In addition, the swinging element 12 has an engaging portion 121 at the top end. By virtue of the elasticity of the plastic material of which the swinging element 12 is made, the engaging portion 121 is fixedly engaged with the eccentric shaft 100 through the engaging action of the plastic material.
The bottom end of the swinging element 12 is formed as a swinging portion 122. When the eccentric shaft 100 is rotated eccentrically, the swinging element 12 is driven by the eccentric shaft 100 such that the swinging portion 122 swings longitudinally, i.e., up and down along the axial direction of the eyebrow tattoo machine 1. On the other hand, the top end of the linking member 13 is pivotally connected to the swinging portion 122, and the bottom end of the linking member 13 is connected to a needle (not shown) of the eyebrow tattoo machine 1 by other components. When the eccentric shaft 100 drives the swinging element 12 and thereby drives the swinging portion 122 to swing longitudinally, the linking member 13 is moved up and down with the swinging portion 122 to impart vertical oscillation, which enables the insertion of a liquid dye preparation into the tattooed area. Thus, eyebrow tattooing is carried out.
However, the conventional eyebrow tattoo machine 1 leaves much room for improvement. Referring to FIG. 1, as the swinging element 12 is fixedly engaged with the eccentric shaft 100 by the engaging action of the plastic material of the swinging element 12, the portion of the engaging portion 121 that is adjacent to the eccentric shaft 100 tends to be permanently deformed after the eyebrow tattoo machine 1 is used for a long time. Should it happen, the engaging portion 121 may become loose from the eccentric shaft 100, causing ineffective power transmission from the motor 10 to the swinging element 12. Even worse, the swinging element 12 and the linking member 13 may shake in an undesirable manner, thus shortening the service life of the eyebrow tattoo machine 1 and, in the end, incurring expenses for buying a new eyebrow tattoo machine. Moreover, when the eyebrow tattoo machine 1 is used in an area of relatively high hardness, such as where the eyebrow bone lies, the linking member 13 and the needle connected thereto may be shifted angularly and therefore lead to erroneous operation of the eyebrow tattoo machine 1. Such erroneous operation not only compromises the efficiency of the eyebrow tattooing procedure seriously, but also may cause irremediable defects on customers' faces. While attempts have been made to make the swinging element 12 out of metal as a solution to the aforesaid plastic deformation problem, the metallic swinging element 12 has its own drawbacks. For example, friction with the metallic swinging element 12 tends to generate high heat, and the adjacent components are very likely to deteriorate after long-term exposure to such high heat. As a result, an eyebrow tattoo machine with the metallic swinging element 12 still has a shortened service life, which translates into a monetary burden on the user.
Therefore, the issue to be addressed by the present invention is to overcome the various problems of the transmission mechanism of the conventional eyebrow tattoo machines (e.g., the loosening of deformed plastic parts, the generation of high heat by metallic components, and so on) and design an improved transmission mechanism capable of delivering a vertical actuating force steadily to the tattoo needle(s) to prevent the needle(s) from being shifted angularly.